Investigation Of Application Potential Of Ag-carrying Antimicrobial Materials And Hinokitiol As Active Components Of Seed-coating Preparations For Plant Disease Control

The author investigated the suppression of Ag-carrying inorganic antimicrobial agents Zeomic, AM1and botanical antimicrobial agent Hinokitiol against fungi, bacteria and plant parasitic nematodes and thediseases they incited. Results showed that Zeomic highly inhibited spore germination, and slightlysuppressed colony expansion of the tested fungal pathogens. It completely inhibited spore germination ofFusarium oxysporum and F. solani at 500mg/L andkilled 99.6% of vegetableroot-knot nematode and allsecond juveniles of soybeancyst nematode after 48 hours of treatment at 250 mg/L.AM1inhibited colonyexpansion of Phytophthora sojae,F. oxysporum andRhizoctonia solani AG4 byover 50% at concentrationrange from 250 to 1000 mg/L, with EC50s 2246, 831.9, 582.3 and 488.97mg/L to F. oxysporum,R.solani,Gaeumannomyces graminia and Helminthosporium sativum, respectively. Hinokitiol completelyinhibited spore germination of F.oxysporum at 250mg/L, andstronglysuppressed colonyexpansion of thepathogens at 100mg/L.Its EC50s were 8.31, 10.05, 16.9 and 12.25 mg/Lto R. solani AG1, R.cerealis, R.solani AG4isolatedfromsoybean,R.solaniAG4fromcotton, respectively.Hinokitiolcompletelyinhibitedthe growth of Pseudomonas solanacearum at 50mg/L, and inhibited growth of Stenotrophomonasmaltophilia by91.1%at100mg/L.Survey on the plant development and growth indicated that the tested antimicrobial agents greatlypromoted seedling growth, and did not show any negative effect on seeds germination andemergence andseedlings growth of soybean, wheat, cotton and maize. Seed-coating with AM1significantly reduced theincidences of soybean root rot diseases caused byR. solani, F. solani and F. oxysporum under greenhouseconditions by 49.8, 80.6 and 64.9%, respectively. Seed coating with Zeomic, AM1 andHinokitiol reducedthe cotton wilt diseases caused by F. oxysporumsf.sp. vasinfectum and Verticillium dahliae by 16.5, 45.8,34.4% and 24.1, 20.2, 39.2%, respectively, in greenhouse. Field tests showed that seed-coating with AM1reducedincidencesof soybeanrootrot, wheatsharpeyespot,wheattake-allandcottonseedlingdiseases by32.6, 71.0, 77.9 and 33.1%, respectively. Yields of soybean and wheat were increased byup to 10.1% and20.8%,respectively,incomparison withthose ofCK.Investigation of the mode of action indicated that AM1 suppressed R. solani AG4, F. solani and F.oxysporum by shortening mycelial branches, malforming hypha, reducing sporulation, producing vesiclestructures, disruptinghyphalcellwalls,andinhibitingsporegermination.